The present invention relates generally to a numerically controlled machine tool and to an operator work management system.
A numerical control unit is designed to perform numerical control processing in accordance with a cutting program provided by a paper tape, etc. Specifically, a machine tool is driven according to the results of the control processing in order to cut a workpiece.
FIG. 10 is a block diagram of a prior art numerical control unit. A cutting program read from a tape reader 11 is stored into a memory 18. When this cutting program is to be executed, it is first read from the memory 18 block by block and then processed in a controller 12 containing a processor, a control program memory, etc. The controller 12 then performs numerical control processing in accordance with the cutting program, thereby driving a servo motor of a machine tool 14 so as to move a table or a tool rest in accordance with a move command, or for controlling the machine tool 14, via an electrical control box 13, to perform, for example, coolant on/off and spindle run/reverse/stop commands. The numeral 15 indicates an operation board including zeroing, Jogging and other command switches, buttons and indicators. The numeral 16 is a manual data input device (hereinafter referred to as the "MDI") for manually entering various types of data into the controller 12, and numeral 17 is a display unit ("DSP") for displaying the current position and other data of the machine. The components 11 to 17 (with the exception of the machine tool 14) constitute a computerized numerical control unit (hereinafter referred to as a "CNC"). The controller 12 in the CNC is a computer which performs predetermined numerical control processing on the basis of a control program and the cutting program to control the machine tool 14.
The machine tool 14 controlled by the CNC is referred to as a numerically controlled machine tool (NC machine tool), and most of the present machine tools are NC machine tools. The operator controlling this NC machine tool is usually provided with work directives through cutting programs for cutting workpieces to be finished on that day, and work setup instructions as a preliminary to cutting. The operator carries out the setup work in accordance with the work instruction and causes the CNC to run the predetermined cutting programs to cut workpieces. The operator then writes the work done on that day in a work report or the like. The NC machine tool may generally be operated by any person including unauthorized personnel by simply powering up. To prevent this, some CNCs have a function of disabling NC data from being rewritten unless a key provided therefor is switched on.
Further, recent CNCs holding a larger internal memory capacity have a function of allowing the keying history of the operator to be stored in an internal memory for a later check of the operation performed. Further, some CNCs allow CNC-generated error, alarm and other histories to be stored in an internal memory, so that errors and alarms occurring at various times can be checked later.
Furthermore, there is a growing tendency for recent CNCs to display messages, etc. for the operator on a display device to allow the operator to "converse" with the CNC and be guided during operation, thereby improving the operability of the CNC. To allow kanji (Chinese characters), kana (Japanese phonetic characters) and other characters to be displayed for this purpose, in addition to the roman alphabet and numerals, the NC contains character fonts which are employed to display kanji, kana and other characters.
FIG. 12 is a block diagram illustrating the major parts of a prior art CNC display control section, wherein the numeral 60 indicates a microcomputer; 61 a ROM for storing programs and other data required for the microcomputer 60 to perform predetermined operations, 59 a RAM used for pointers, operation, etc., 62 an address decoder for accessing memories, etc., and 63 a first-An first-out register (FIFO register) to which display data is written from a host microcomputer for NC control (not illustrated) and which is designed to issue an interrupt signal INT to the microcomputer 60 when, for example, data of 16 characters is entered. The numeral 64 indicates a CRT controller for generating horizontal and vertical synchronization signals and scanning addresses, 65 a pulse generator circuit, 66 an address switching circuit for switching between a CPU address and a scanning address, 67 an address decoder, 68 a character RAM (video RAM) for storing characters coded into addresses corresponding to the positions on a display screen, 69 a color RAM (video RAM) for storing colors for painting characters on the display screen, 70 a character ROM for converting character codes output by the character RAM 68 into corresponding display data (alphabetic characters, kanji, kana and symbols), 71 a display control circuit for outputting red, green and blue video signals in accordance with the output of the color RAM 69, 17 a display unit,. and 72 a screen thereof.
A character string to be displayed on the screen 72 of the display unit 17 is entered sequentially from the NC controlling microcomputer (not illustrated) to the FIFO register 63. A character in this character string is coded, for example, in sixteen bits. When a character code of sixteen characters is entered into the FIFO register 63, the microcomputer 60 is interrupted to perform interrupt processing. In other words, the character code is read from the FIFO register 63 and written to the separately specified address of the character RAM 68.
When color designating information is then entered into the FIFO register 63, that information is read and color information is written to the corresponding area of the color RAM 69. When the information is written to the RAMs 68 and 69, the address switching circuit 66 is switched to the scanning address position of the CRT controller 64 whereby the contents of the character RAM 68 and the color RAM 69 at the scanning addresses are read in synchronization with each other. The output of the character RAM 68 is provided in character code and converted into display character data in the character RAM 70. Namely, if that character code is a kanji code, multiple pieces of dot data matching the shape of that kanji character are outputted. According to that dot data and the color information of the color RAM 69, the display control circuit 71 creates red, green and blue video signals, which are then input to the display unit 17 and displayed as a character on the screen 72. Accordingly, the use of the kanji and kana characters to form a character string sent from the NC controlling host microcomputer allows comments and other guides to be displayed in kanji and other characters which can be most easily understood by the Japanese. Since not many terms are employed in the NC field, the number of kanji characters used is limited. Hence, the character ROM can be composed of a single LSI for characters including kana.
Since the known display control device shown in FIG. 12 is configured as described above, the character ROM 70 must be replaced to display characters corresponding to the user's native language and the display language cannot be changed easily. To improve this disadvantage, a display control section wherein the character ROM 70 is replaced by a character RAM and the data of the character RAM is changed through the key switches of the operation panel for use with a numerical control unit is disclosed in Japanese Patent Disclosure Publication No. 189785 (1985).
In the NC machine tool known in the art which has only the aforementioned functions, a work instruction containing all work directives for the operator and a cutting program must be passed to the operator in pairs and both must always be managed at the same time. In addition, before starting the cutting operation, the operator needs to check various pieces of data (parameters, tool information, etc.) in the CNC to see if they are appropriate. Since all setup prior to the cutting is left to the operator, defects may occur due to operator errors, e.g. workpieces may be machined with a different parameter value.
In addition, because a work report is written by the operator, there may be incorrect or omitted entries, and further the operator may leave things out when inconvenient for himself or herself. Moreover, when it is desired to make the NC machine tool operable only for particular operators, the key of the CNC must be passed to each operator, and further, the absence of this key simply disallows the internal data of the CNC from being changed and the NC machine tool itself can be operated as desired.